Transcript for Genetic genealogy solves 1984 Wisconsin cold case
A hunt for killer that spanned more than three decades now investigators know who murdered this eat teen year old from sock sale. After almost 35 years we found the person. But it brutally raped. Strangled. In blunt increasing and revert to them. That man has been identified it's still across the convicted felon who died from a drug overdose in 2012. December 14 1984. And Herbert was at a house party in Port Washington with friends is lucky county sheriff says she left to walk a few miles to work moments sock feel. But never made it the next morning her half naked body was found in the driveway of a home in the town of Grafton. Process second shift employment a wrestler. Will allow him to be at a Port Washington area. The time the Tracy left on foot from her friend's residence investigators had the killer's DNA but. After 400 samples were tested in the state crime lab we don't match. In March using forensic genetic genealogy. 11 Los Angeles linked Philip crossed the murder that we mix mixed June. I wanted in the face greater justice. He stole Tracy's life and police say all these years he's never considered a suspect they think he stayed. Off your radar. Good question as we talked to hundreds of people but. I don't think he told me that he was able to keep potential.
This transcript has been automatically generated and may not be 100% accurate.